Maritime surface search radars are used in a number of applications such as navigation, search and rescue, law enforcement, defense and the like. They may be sea-based, as on a ship or boat, they may be land-based, as at a shore installation, or they may be air-based, as on an airplane or air ship equipped with radar.
A basic problem with utilizing the data produced by such radars is that the desired information, such as radar scattering from a person or vessel, can be obscured by two forms of sea clutter due to radar reflections from the water surface. A first type of sea clutter is speckle noise scatter which is essentially uncorrelated and random and is caused by effectively random scattering of a portion of the incident radar signal back to the radar unit by the overall water surface. A second type of sea clutter is correlated sea clutter and is due to scattering of the radar signal due to the height, shape and aspect both of waves in the water and of breaking wave events.
Correlated sea clutter tends to degrade the performance of all maritime surface search radars, particular in higher sea state conditions, and it would be desirable to provide a method and apparatus for reducing the effects of sea clutter so as to provide increased performance for maritime surface search radars.